This invention relates to a penetrometer and more particularly to a recording soil penetrometer which provides a depth-penetration resistance graph as the penetrometer is forced into the ground.
Throughout history, man has used his senses to determine soil conditions. He could observe cracks and fissures caused by drying of the soil and could see the rocks, stones and organic material which made up the soil to obtain a visual impression of physical conditions of the soil. He estimated moisture content of the soil by compressing the soil in his hand. If his footprint was shallow, the soil was firm. If he sank in the soil to his knees, he knew the soil was soft. Though these were not exact methods, by trial and error, proper conditions for plant growth were estimated. These experiences were passed from generation to generation.
Various means for measuring soil conditions have been devised. Laboratory analysis of organic matter and nutrients, aggregate sizes, moisture content, biological activity, and shear strength provide knowledge about soil conditions. The penetrometer is one of the instruments used to measure mechanical properties of soil. A penetrometer such as described in ASAE Recommendation: ASAE R313.1 was developed and has been widely used by the Army Corps of Engineers and by highway contractors for a number of years. The size of cone tip used and penetration force can be translated into cone index which is related to penetrating resistance. The normal practice of using the conventional cone penetrometer involves one person pushing the penetrometer into the ground at a uniform rate and another person reading and recording force readings at each increment of depth. The discrete data is then plotted on graph paper to give a depth versus penetrating resistance graph. The described method of operation misses much of the information required by the researcher and results in a graph which is the average of questionable material.
Therefore, it is a principal object of the invention to provide a penetrometer which provides a depth-penetration resistance graph as the penetrometer is forced into the ground to increase the accuracy of the data.
A still further object of the invention is to provide a penetrometer which records all of the necessary required data.
A still further object of the invention is to provide a penetrometer which is portable.
A still further object of the invention is to provide a penetrometer which may be operated in an efficient manner.
A still further object of the invention is to provide a penetrometer which is simple both in construction and operation.
These and other objects will be apparent to those skilled in the art.